This invention relates generally to track apparatus for vehicles and, more particularly, to track apparatus of the type for use in place of a vehicle wheel.
Agricultural vehicles such as tractors, combines and the like are commonly used in agricultural fields for a variety of jobs, and construction vehicles and other large work vehicles are used for many different jobs on a variety of pound surfaces. Typically, these vehicles have tires on which the vehicles are supported on the ground. These kinds of large vehicles are quite heavy, mid their weight is distributed to a relatively small area by the vehicle dyes. As a result the tires of such vehicles tend to compact the soil in the fields or other ground surfaces. Compacted soil discourages growth of crop planted in the fields which need loose soil to flourish, and ground surface compaction is often undesirable for other reasons as well.
In addition, since fields and other work sites are often wet due to rain or watering, vehicles which enter the fields become bogged down in the mud due to the fact that there is such a small tire area in contact wit the ground. Therefore, it is highly desirable to develop a track apparatus for vehicles which spreads vehicle weight over a larger area so as to reduce the degree of pound compaction. Providing a larger ground-surface engagement area also serves to prevent vehicles from becoming bogged down in mud or other soft pound surfaces.
Prior track apparatuses for vehicles are disclosed in U.S. Pat. Nos. Re36,284 (Kelderman) and 5,829,848 (Kelderman), assigned to the assignee of the print invention and incorporated herein by reference. The Kelderman ""284 reissue and ""848 patents disclose track suspension systems for vehicles having a frame and a continuous rubber track. The drive wheel is attached to the frame for engaging and driving the continuous flexible track.
In certain track apparatus of the prior art, distortion of the track apparatus frame during use may cause excessive stresses thereon and failure of the track apparatus flame may result. Furthermore, the flexible track of such buck apparatus is subject to excessive forces which can result in premature wear. Unacceptable frame distortion can also interfere with efficient operation of such track apparatus. There is a need for an improved track apparatus with a frame having improved resistance to distortion.
It is an object of this invention to provide an improved track apparatus, of the type for use in place of a vehicle wheel, which overcomes some of the problems and shortcomings of the prior art, including those referred to above.
More particularly, it is an object of this invention to provide an improved back apparatus reducing or eliminating frame distortion and related problems.
Another object of the invention is to provide a track apparatus having a frame of superior strength and rigidity, and consequent improved resistance to distortion.
Yet another object of the invention to provide a track apparatus which is inexpensive and simple to manufacture.
In accordance with the present invention, at improved track apparatus of the type mountable on the rotatable axle of a vehicle is provided with a frame of improve construction. The track apparatus, in addition to its continuous flexible track with its upper and lower portions, includes: a frame, the characteristics of which will be described below; a drive wheel rotatably mounted with respect to the frame and having an upper circumferential portion engageable with the inner surface of the upper portion of the flexible track and a lower circumferential portion spaced above the lower portion of the track; and leading and trailing idler wheels. The frame of this invention is a rigid structure including first and second side portions which define a drive wheel receipt well therebetween for receiving the drive wheel of the track apparatus.
The first and second side portions include leading apparatus therethrough and trailing apertures therethrough such that the leading apertures are in axial alignment with each other and the trailing apertures are in axial alignment with each other. The first and second side portions are interconnected by a rigid leading cross-member extending between the first side portion adjacent to the leading aperture therein and the second side portion adjacent to the leading aperture therein. In highly referred embodiments of this invention, the frame is of uni-body construction, providing excellent rigidity and case of construction.
The leading cross-member is a preferably a pivot shroud, i.e., a shroud for a pivot pin which pivotably supports a idler mounting bucket with respect to the rigid frame. Such bracket supports idler mounts for leading idler wheels. The preferred shroud for the pivot pin is most preferably a sleeve trough which the pivot pin extends to pivotably sipped the idler mounting bracket.
In preferred embodiments, the side portions are also interconnected by a rigid trailing cross-member extending between the first side portion adjacent to the trailing aperture therein and the second side portion adjacent to the trailing aperture therein. The trailing cross-member is preferably a trailing-idler-axle shroud; most preferably, the trailing shroud is a sleeve through which the trailing-idler axle extends.
The first and second side portions of the frame are preferably also interconnected by front and rear end panels.
The first side portion of the frame preferably includes a spindle hub for rotatably receiving an axle of a vehicle therein for engagement with the track apparatus drive wheel. The frame preferably also includes a bracket support arm which depends from the front panel, the bracket support arms each having a terminal end which defines one of the aforementioned two leading apertures. Such apertures provide a pivot location for pivotably receiving the pivot pin.
The preferred track apparatus includes trailing-idler support arms which extend from the rear panel. Each trailing-idler support arm preferably has one of the trailing apertures thereon. Such trailing apertures provide a location for rotatably receiving a trailing-idler axle therethrough.
In preferred embodiments, the frame includes a leading-bogey mount for rotatably supporting a leading-bogey wheel which engages the flexible track. In such preferred embodiments, the side portions are connected by a rigid leading-bogey cross-member extending between the first side portion adjacent to the leading-bogey mount and the second side portion adjacent to the leading-bogey mount. It is highly preferable that the leading-bogey cross-member be a leading-bogey axle shroud. Such a leading-bogey axle shroud is most preferably a sleeve through which the leading bogey axle extends.
The frame also preferably includes a trailing-bogey mount for rotatably supporting a trailing-bogey wheel which engages the track. The side portions are preferably further connected by a rigid trailing-bogey cross-member extending between the first side portion adjacent to the trailing-bogey mount and the second side portion adjacent to the trailing-bogey mount. It is preferred that the trailing-bogey cross-member be a trailing-bogey axle shroud. In such preferred embodiments, the trailing-bogey mount is most preferably a trailing-bogey axle and the trailing-bogey axle-shroud is a sleeve through which the trailing bogey axle extends.
The invention may be described differently as being a track apparatus having (1) a plurality of wheels engaging the inner stake of the track, including a drive wheel (as motioned above), leading and trailing idler wheels, and preferably at least one bogey wheel engaging only a middle portion of the lower length of the track, and (2) a frame for mounting the wheels. The frame has a uni-body construction such that it includes fixed-mounts in fixed relative positions. Each fixed-mount which is preferably an aperture (or pair of aligned apertures) in the frame for receiving an axle therethrough, defines an axis and provides mounting as follows:
The drive wheel is rotatably mounted to one of the fixed-mounts and turns on its axis. One of the idler wheels (a xe2x80x9cfirstxe2x80x9d idler wheel) is rotatably mounted to another of the fixed-mounts, i.e., a fixed-mount at a rearwardmost or forwardmost position on the frame, and turns on the axis of such fixed-mount. An idler-mounting bracket is pivotably mounted to another of the fixed-mounts, i.e., the fixed-mount at the opposite end of the frame (e.g., the forward most end), and such bracket pivots on the axis of such fixed-mount. The bracket itself has an idler-mount which defines an idler-mount axis at which the other idler wheel (a xe2x80x9csecondxe2x80x9d idler wheel) is rotatably mounted in variable positions with respect to the frame. (Such idler-mount axis is spaced from and movable with respect to the axis of the fixed-mount about which the bracket pivots, to facilitate tensioning of the flexible track and accommodation of ground-surface irregularities.) Each bogey wheel (there may be one, two or more bogey wheels) is rotatably mounted to a respective one of the fixed-mounts (in an intermediate position on the frame) and turns on the axis of its respective fixed-mount.
In certain preferred embodiments, the first wheel is the trailing idler wheel and the second wheel is the leading idler wheel. In highly preferred embodiments, there are a pair of axially-aligned leading idler wheels and a pair of axially-aligned trailing idler wheels.
In other preferred embodiments, the frame defines a lateral recess receiving the drive wheel. More preferably, the frame include first and second side portions which define the lateral recess, or drive wheel receipt well.